Tow-haul transmission c1500 chev question

[jimdana1942]

Can anyone tell me exactly what the tow-haul button on the shift selector on a 2002 chevy silverado causes the transmission to do when it is selected?

 

[BOSS302]

Changes transmission shift parameters.

 

[RopeS]

Changes transmission shift parameters.

Yep, what he said. Usually holds the gears out longer I believe.

 

[Guate_shooter]

gives you more rum rum for pulling hahahahahhaa,

what both of the guys above said, by changing the shift parameters it holds the gear just a few seconds longer focusing mostly on torque and not so much speed, usually mostly needed when taking off.

 

[Gus McCrae]

It's designed to keep the transmission from "searching" when the load gets heavy. Before these were normal, if you were hauling a big boat in 84 Chevrolet with a 4 speed auto, the truck might bounce back and fourth between gears 3 and 4. The solution was to drop it back into 3rd (effectively making it like a Turbo 350) and drive with it like that.

It's a good thing to use when you load your truck down with a heavy load. It'll make your transmission last longer.

 

[BOSS302]

How detailed do you want? I can shoot you the tune file if you've got efi live.

NO TC lockup out of OD
NO OD until 59MPH
Increased line pressure
Allows for Free-revving
Holds the gears to keep the RPM in powerband

 

[david mitchell]

locks out the torque converter from Overdrive

Torque converter lock out.

 

[paddle007]

If you have a 4L60E transmission,pay attention. If you tow much weight with your vehicle, DO NOT tow in overdrive and push the tow haul button. It's the gonna save your ass a whole bunch of money option. The overdrive is weak on these transmissions and will strip eventually. It will fail much sooner if you tow.
The button does not keep it out of overdrive, only the shifter position.
I have seen units fail well under 100K. Just got back from trailering two motorcycles behind an Siverado. Made it to CO and on the way back we got to spend some extra time in Amarillo because of the sudden loss of our transmision. What a PITA it was.

 

[edman87k5]

Read boss302 and paddle007 above, that says it all.
If you tow big loads on anything but flat,level highway, do NOT use overdrive- no matter the vehicle.

I am sure some allison guys will chime in here and that is almost the only exception I can think of.
Reminds me of my dad with his 7.3/ 4l60e that he went thru 4 factory transmissions in 100k because "It wont go over 70 unless it is in overdrive (with 8k-12k loads)". He sold it with trans #5 acting up at 130k. He was also too cheap to shell out 2000 or more on a quality trans, at least the first 4 were warranty covered.

 

[jimdana1942]

What would constitute a heavy load? Would it be anything within the towing specs of the truck?

 

[edman87k5]

I would personally say anything over about 2k pounds, but opinions will vary widely. Wind resistance will affect it also.

 

[posse comatosis]

If you're towing over 600-700 lbs, probably best to keep it out of overdrive with the shift lever and engage the towing button which will better modulate your transmission better under load. Light stuff like a jon boat, motor and trailer I don't worry about the button, but do run with the modulator in city traffic no matter what the load.

 

[jimdana1942]

If you're towing over 600-700 lbs, probably best to keep it out of overdrive with the shift lever and engage the towing button which will better modulate your transmission better under load. Light stuff like a jon boat, motor and trailer I don't worry about the button, but do run with the modulator in city traffic no matter what the load.

You recommend using the button in city driving even when not towing?

 

[posse comatosis]

Not necessary, I suppose, but sometimes in stop and go traffic or rough road conditions I use it when not towing. The other day I was on a really, really rough road in the Sabine River Bottom and clicked it on. Holds your ground speed under down and eliminates that shifting surge between potholes. Didn't see hog sign one.

 

[Suburbazine]

You recommend using the button in city driving even when not towing?

If you have electronic suspension it makes the ride sportier, too.